This invention relates to a new and improved attachment for chain saws, designed for adapting the saw to cut small branches, limbs and brush-like material without weakening the saw blade holder or causing undesired kickback.
A variety of chain saw attachments having particular application in cutting small diameter branches are known, and typical prior art devices are shown in U.S. Pat. Nos. 2,698,034; 2,813,556; 2,821,213; 2,902,065; 2,925,105; 2,930,416; 2,948,310; 3,380,493; 3,995,370; 4,270,272; 5,150,524. Some of these patents describe devices which provide an effective means for cradling small limbs and branches in the bight created between the saw blade attachment and the cutting chain. While many of these devices allow the force of the blade to compress and align the small diameter branches in the bight while the teeth of the chain saw cut through the foliage, these devices frequently weaken the saw blade holder or increase chain saw vibration. This will occur due to the distribution of stress over a limited section of the saw blade holder; or by inadequate attachment of these devices to the saw blade holder or to each other; or, by connection of the chain saw attachment to only one side of the saw blade holder.
However, none of the prior art devices provides a reinforcing and cutting attachment that more uniformly distributes the weight of the material being cut and distributes the force vector from the rotating chain saw blade more uniformly over a substantial length of the saw blade. Also, these prior art devices reduce the efficiency of the cutting operation due to vibration of the saw blade holder, and the vibration itself may induce structural failure.
Moreover, none of the prior art devices provide an attachment of sufficient stiffness and shear resistance to relieve instantaneous shocks or forces due to jamming or kickback along the longitudinal portion of the chain saw rather than along the attachment that holds the material being cut. Also, it would be helpful if the device could be quickly and easily installed, removed and reattached with a minimal amount of tools.